﴿ قُلْ فَأْتُوا۟ بِكِتَٰبٍۢ مِّنْ عِندِ ٱللَّهِ هُوَ أَهْدَىٰ مِنْهُمَآ أَتَّبِعْهُ إِن كُنتُمْ صَٰدِقِينَ ﴾

“Say: “Produce, then, [another] revelation from God which would offer better guidance than either of these two [and] I shall follow it, if you speak the truth!””

Please check ayah 28:51 for complete tafsir.